Orthopaedic surgical instrumentation for performing a patellofemoral arthroplasty procedure

ABSTRACT

A method and instrumentation for performing a patellofemoral arthroplasty orthopedic procedure includes coupling an anterior cutting block to a femur of a patient such that the cutting block references local anatomy of the femur. The anterior cutting block is used to perform a number of bone cuts to establish a trochlear cavity in the femur. The trochlear cavity is formed such that a trochlear prosthesis may be inset into the cavity and substantially flush with the surrounding cartilage. A finishing burring guide and burr bit may be used to detail the shape and/or size of the trochlear cavity. Additionally, a trochlear drill guide may be used to facilitate establishing peg holes in the patient&#39;s femur to receive corresponding pegs of the trochlear prosthesis.

CROSS-REFERENCE TO RELATED U.S. PATENT APPLICATIONS

This application claims priority to U.S. Utility patent application Ser.No. 12/512,539, which claimed priority under 35 U.S.C. § 119(e) to U.S.Provisional Patent Application Ser. No. 61/085,805 entitled “Method andInstrumentation for Performing a Patellofemoral Arthroplasty OrthopaedicProcedure,” by Lisa Major et al., which was filed on Aug. 1, 2008, theentirety of each which is hereby incorporated by reference.

Cross-reference is also made to co-pending U.S. Utility patentapplication Ser. No. 12/512,543 entitled “Orthopaedic Surgical Methodfor Performing a Patellofemoral Arthroplasty Procedure,” by Lisa Majoret al., the entirety of which is hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates generally to methods and instrumentationfor performing an orthopaedic surgical procedure, and particularly tomethods and associated instrumentation for performing a patellofemoralarthroplasty orthopaedic surgical procedure.

BACKGROUND

Joint arthroplasty is a surgical procedure by which a diseased and/ordamaged natural joint is replaced by a prosthetic joint. Patellofemoralarthroplasty is a type of joint arthroplasty wherein the anteriorcompartment of a patient's knee, or portion thereof, is replaced withone or more prosthetic components. Additionally, in some cases, thepatient's patella may be replaced by an orthopaedic prosthesis.

Typical patellofemoral arthroplasty procedures may include replacing apatient's femoral trochlea, and in some cases, one or both femoralcondyles with prosthetic components. Typical orthopaedic surgicalprocedures require the entire anterior femur to be resectioned to allowoverlay of the prosthetic joint components. However, the prostheticjoint components may not replace the entire volume of resectioned bone.Additionally, many patellofemoral arthroplasty procedures andinstrumentation reference off of the intramedullary canal of thepatient's femur, which resultantly compromises the intrameduallarycanal.

SUMMARY

According to one aspect, an orthopaedic surgical instrument may includea femoral cutting block. The femoral cutting block may include a body, afirst vertical cutting guide, a second vertical cutting guide and ahorizontal cutting guide. The body may have a bone-facing surface havinga contour corresponding to at least a portion of an upper surface of anassociated trochlear prosthesis. The femoral cutting block may alsoinclude a distal boss extending outwardly from the bone-facing surface.The distal boss may include a first passageway extending therethrough.

In some embodiments, the first and second vertical cutting guides may beembodied as open cutting guides. Additionally, the horizontal cuttingguide may be embodied as a closed cutting guide. The first verticalcutting guide may define a first cutting plane and the second verticalcutting guide may define a second cutting plane. In some embodiments,the second cutting plane may be non-parallel to the first cutting plane.Additionally, in some embodiments, the first vertical cutting guide maybe embodied as a medial cutting guide, the second vertical cutting guidemay be embodied as a lateral cutting guide, and the horizontal cuttingguide may be embodied as an anterior cutting guide. The first verticalcutting guide may be defined by a first sidewall extending upwardly fromthe body a first distance and the second vertical cutting guide may bedefined by a second sidewall extending upwardly from the body a seconddistance. In some embodiments, the second distance being greater thanthe first distance.

In some embodiments, the femoral cutting block may also include an armremovably coupled to the body and extending therefrom. In suchembodiments, the femoral cutting block may include a boss extendingupwardly from an upper surface of the body. The arm may include anaperture sized to receive the boss to couple the arm to the body.Additionally, the arm may be pivotable about the boss. In someembodiments, the boss may include an upper surface and an alignment linedefined on the upper surface. In such embodiments, the alignment linemay be substantially perpendicular to the bone-facing surface of thebody.

In some embodiments, the body may include an upper body section and alower body section extending downwardly from the upper body section. Thelower body section may include a second passageway oblique to the firstpassageway. Additionally, in some embodiments, the femoral cutting blockmay include a tab extending downwardly from the lower body section. Thetab may be positioned and sized to contact the distal cartilage of apatient's femur when the femoral cutting block is coupled thereto. Forexample, in some embodiments, the tab may extend downwardly from thelower body section a distance of about two millimeters. Additionally,the femoral cutting block may include a mount coupled to an uppersurface of the body, the mount being configured to couple with a tool toposition the orthopaedic surgical instrument without touching thefemoral cutting block.

According to another aspect, an orthopaedic burring guide may include aframe having a curved bone-facing side. The frame may define a firstopening and a second opening separate from the first opening. Theburring guide may also include a distal boss extending from thebone-facing side of the frame. The distal boss may include a passagewaydefined therein. The orthopaedic burring guide may further include abase extending downwardly from the frame. The base may be sized to bereceived in a surgically-prepared trochlear cavity of a patient'santerior femur. The base may include a first and second mounting holedefined therethrough. In some embodiments, the orthopaedic burring guidemay also include a tab extending downwardly from the distal boss. Insuch embodiments, the tab may have a length less than the distal boss.Additionally, in some embodiments, the base may have a thicknesssubstantially equal to the depth of the anterior trochlear cavity.

According to another aspect, a trochlear drill guide may include a bodyhaving a first passageway and a second passageway defined therethrough,a first drill guide bushing positioned in the first passageway, and asecond drill guide bushing positioned in the second passageway. Thefirst drill guide bushing may be movable within the first passageway.The first drill guide bushing may also include a first inner passagewaydefined therethrough. Similarly, the second drill guide bushing may bemovable within the second passageway and may include a second innerpassageway defined therethrough.

In some embodiments, the first and second drill guide bushings may beseparately movable. Additionally, the first and second drill guidebushings may be movable along a longitudinal axis defined by therespective first and second passageways. Further, in some embodiments,the first drill guide bushing may include a first end, a first collarcoupled to the first end, a second end opposite the first end, and asecond collar coupled to the second end. In such embodiments, the firstdrill guide bushing may be movable within the first passageway between afirst position in which the first collar extends out of the firstpassageway and a second position wherein the second collar extends outof the first passageway. Similarly, the second drill guide bushing mayinclude a third end, a third collar coupled to the third end, a fourthend opposite the third end, and a fourth collar coupled to the fourthend. The second drill guide bushing may be movable within the secondpassageway between a third position in which the third collar extendsout of the second passageway and a fourth position wherein the fourthcollar extends out of the second passageway.

In some embodiments, the trochlear drill guide may also include a mountcoupled to the body and extending therefrom. The mount may include afirst mounting base located at a first end and a second mounting baselocated at a second end opposite the first end. The mount may define akeyed structure to be received in a corresponding keyed recess. Forexample, in some embodiments, the mount may include a first keyedprotrusion extending from a first side of the first mounting base and asecond keyed protrusion extending from a second side of the secondmounting base.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the following figures,in which:

FIGS. 1A and 1B are a flowchart of a method for performing anorthopaedic surgical procedure;

FIG. 2 is a side elevational view of an anterior femoral cutting blockfor use with the method of FIG. 1;

FIG. 3 is a front elevational view of the anterior femoral cutting blockof FIG. 2;

FIG. 4 is a top plan view of the anterior femoral cutting block of FIG.2;

FIG. 5 is a side elevational view of the anterior femoral cutting blockof FIG. 2;

FIG. 6 is a rear perspective view of the anterior femoral cutting blockof FIG. 2;

FIG. 7 is another side elevational view of the anterior femoral cuttingblock of FIG. 2;

FIG. 8 is a perspective view of the anterior femoral cutting block ofFIG. 2 positioned on the distal end of a patient's femur;

FIG. 9 is a perspective view of a drill bit used in the method of FIG.1;

FIG. 10 is a perspective view of the patient's femur having a referencehole defined in the distal end of the femur;

FIG. 11 is a perspective view of the anterior femoral cutting block ofFIG. 2 attached to the patient's femur;

FIG. 12 is a perspective view of a bone saw performing a vertical boneresectioning cut on the patient's femur using the anterior femoralcutting block of FIG. 2;

FIG. 13 is a top elevational view of the anterior femoral cutting blockof FIG. 2 and a trochlear prosthesis;

FIG. 14 is a perspective view of a bone saw performing a horizontal boneresectioning cut on the patient's femur using the anterior femoralcutting block of FIG. 2;

FIG. 15 is a perspective view of a finishing burring guide for use withthe method of FIG. 1;

FIG. 16 is a side elevational view of the finishing burring guide ofFIG. 15;

FIG. 17 is a perspective view of the finishing burring guide of FIG. 15being coupled to the distal end of the patient's femur;

FIG. 18 is a top elevational view of the finishing burring guide of FIG.15 and the trochlear prosthesis;

FIG. 19 is a perspective view of a burring bit for use with thefinishing burring guide of FIG. 15;

FIG. 20 is a perspective view of the burring bit of FIG. 19 used withthe finishing burring guide of FIG. 15 to remove a portion of thepatient's anterior and distal femur;

FIG. 21 is a top plan view of a pegless trochlear prosthetic trial foruse in the method of FIG. 1;

FIG. 22 is a perspective view of a trochlear drill guide for use withthe method of FIG. 1;

FIG. 23 is another perspective view of the trochlear drill guide of FIG.22;

FIG. 24 is a perspective view of the trochlear drill guide of FIG. 22coupled to the patient's femur; and

FIG. 25 is a perspective view of the trochlear drill guide of FIG. 22secured to the patient's femur during an orthopaedic drilling procedure.

DETAILED DESCRIPTION OF THE DRAWINGS

While the concepts of the present disclosure are susceptible to variousmodifications and alternative forms, specific exemplary embodimentsthereof have been shown by way of example in the drawings and willherein be described in detail. It should be understood, however, thatthere is no intent to limit the concepts of the present disclosure tothe particular forms disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

Terms representing anatomical references, such as anterior, posterior,medial, lateral, superior, inferior, etcetera, may be used throughoutthis disclosure in reference to both the orthopaedic implants describedherein and a patient's natural anatomy. Such terms have well-understoodmeanings in both the study of anatomy and the field of orthopaedics. Useof such anatomical reference terms in the specification and claims isintended to be consistent with their well-understood meanings unlessnoted otherwise.

A method 10 for performing a patellofemoral arthroplasty orthopaedicprocedure to replace a portion of a patient's femoral trochlea with atrochlear orthopaedic prosthesis is illustrated in FIGS. 1a and 1b . Themethod 10 begins with a step 12 in which a reference point of thepatient's relevant femur is located. This reference point is usedthroughout the method 10 to position various surgical instrumentation asdiscussed in more detail below. In the embodiment of FIG. 1, the localreference point is defined as the roof of the intercondylar notch of thepatient's relevant femur. Once identified, this reference point is usedto position the surgical instruments by referencing each instrument tothe roof of the patient's intercondylar notch.

After the reference point has been determined in step 12, an anteriorfemoral cutting block 100 is sized and coupled to the patient's relevantfemur in step 14. The anterior femoral cutting block 100 is used toperform a number of bone cuts on the patient's femur as discussed inmore detail below. One embodiment of an anterior femoral cutting block100 used with the method 10 is illustrated in FIGS. 2-14. The cuttingblock 100 includes a cutting block body 102 and a sizing arm 104 coupledto the cutting block body 102. The cutting block body 102 includes anupper body 106 and a lower body 108 extending downwardly from the upperbody 106. The sizing arm 104 is coupled to a top side 110 of the upperbody 106. In the illustrative embodiment, the upper body 106 has asubstantially rectangular shape and the lower body 108 has asubstantially triangular shape. However, in other embodiments, the upperand lower bodies 106, 108 of the cutting block 100 may have othershapes.

The upper body 106 of the cutting block body 102 includes a horizontalcutting guide 114 and two vertical cutting guides 116, 118. In theillustrative embodiment, the horizontal cutting guide 114 is embodied asa captured cutting guide and the vertical cutting guides 116, 118 areembodied as non-captured or opened cutting guides. However, in otherembodiments, other types of cutting guides may be used.

The vertical cutting guide 116 is defined, in part, by a side wall 120that extends upwardly from the upper body 106. Similarly, the verticalcutting guide 118 is defined, in part, by a side wall 122 that extendsupwardly from the upper body 106. In the illustrative embodiment, theside walls 120, 122 have different heights. That is, the wall 120extends upwardly from the upper body 106 a distance 124 and the wall 122extends upwardly from the upper body 106 a distance 126 that isdifferent from the distance 124. However, in other embodiments, thewalls 120, 122 may extend upwardly from the upper body 106 the samedistance (i.e., the distances 124 and 126 may be substantially equal).Each of the walls 122, 124 includes a top surface 128, 130,respectively, which are used to axially align the anterior femoralcutting block 100 relative the patient's femur as discussed in moredetail below. In the illustrative embodiments, the vertical cuttingguides 116, 118 are defined such that the cutting planes defined therebyare non-parallel. That is, as illustrated in FIG. 6, a cutting plane 144defined by the vertical cutting guide 116 is non-parallel to a cuttingplane 146 defined by the cutting guide 118. However, in otherembodiments, the vertical cutting guides 116, 118 may define parallelcutting planes (i.e., the cutting planes 144, 146 may be substantiallyparallel). In some embodiments, the upper body 106 may include a line orindicia 131 extending between and aligned with the top surfaces 128, 130of the walls 120, 122, which may be used to orient the anterior cuttingblock 102 as discussed in more detail below.

As discussed above, the upper body 106 of the cutting block body 102includes a top side 110 to which the sizing arm 104 is coupled. A peg orboss 132 extends upwardly from the top side 110. The peg 132 is used tocouple the sizing arm 104 to the block body 102. In one particularembodiment, the peg 132 includes a circumferential groove 133 (see FIG.6) to mate with a BAL SEAL® spring assembled into the sizing arm 104.When coupled, the sizing arm 104 is free to rotate about the peg 132. Insome embodiments, the peg 132 may include an alignment line or indicia134 (see FIG. 4) defined on a top surface 136 of the boss 132. Thealignment line 134 is perpendicular to a bone-facing side of the cuttingblock body 102. The alignment line 134 may be used to align the sizingarm 104 in a position that is substantially perpendicular to the cuttingblock body 102. To do so, the sizing arm 104 may be rotated about theboss 132. In some embodiments, the sizing arm 104 may include acorresponding alignment line 135 (see FIG. 13), which may be used toalign the sizing arm 104 relative to the cutting block body 102 byaligning the lines 134, 135.

The top side 110 of the upper body 106 may also include a base 138 forcoupling a positioning clamp 310 (see FIG. 8) to the cutting block body102. The illustrative base 138 includes a pair of apertures 140 andvertically extending tabs 142 positioned toward the sides of theapertures 140. The apertures 140 and tabs 142 provide a structure towhich the positioning clamp 310 may be coupled to allow the clamp 310 toproperly position the cutting block body 102.

As shown in FIG. 5, the lower body 108 of the cutting block body 102includes an outer side 150 and a bone-confronting side 152. The outerside 150 of the lower body 108 may be substantially planar. However, thebone-confronting side 152 of the lower body 108 is contoured orotherwise curved. In the illustrative embodiment, the curvature of thebone-confronting side 152 matches the curvature of a trochlearorthopaedic prosthesis or implant 300 (see FIG. 7). As such, the cuttingblock body 102 is configured for use with a particular size and side(right knee or left knee implant) of a trochlear prosthesis 300. Whenthe anterior femoral cutting block 100 is coupled to the femur of apatient, the bone-confronting side 152 abuts or confronts the patient'sfemoral cartilage. As such, the Varus/Valgus alignment of the anteriorcutting block 100 can be evaluated by assessing the quality of fit orconformity of the medial and lateral sides of the bone-confronting side152.

The lower body 108 of the cutting block body 102 also includes a distalboss 154, which extends outwardly from the bone-confronting side 152. Asdiscussed below, the boss 154 is configured to be inserted into areference hole or cavity previously formed in the patient's femur tosecure and align the anterior femoral cutting block 100 to the patient'sfemur. The lower body 108 also includes a pair of pin guide holes 156,158 defined therethrough. The pin guide holes 156, 158 are used tosecure the anterior cutting block 102 to the patient's femur using apair of bone pins or similar fixation devices. The pin guide hole 158extends through the distal boss 154. The pin guide hole 156 is locatedsuperiorly and angled relative to the pin guide hole 158 to prevent orotherwise limit the cutting block body 102 from backing off the bonepins during use (e.g., from vibrations generated by a bone saw).

The cutting block body 102 also includes a distal tab 160 that extendsdownwardly from the lower body 108. Illustratively, the tab 160 extendsfrom the lower body 108 a distance 162 (see FIG. 3) such that the tab160 references or otherwise contacts the distal articular cartilage ofthe patient's femur when coupled thereto. In this way, the anteriorcutting block 102 references the distal articular cartilage. In theillustrative embodiment, the distal tab 160 extends from the lower body108 a distance 162 equal to about 2 millimeters. However, in otherembodiments, the tab 160 may extend from the lower body 108 a differentdistance.

It should be appreciated that the anterior cutting block 102 is usableto perform a number of different functions. For example, the size andalignment of the trochlear prosthesis 300 is determined using thecutting block 102. Additionally, the vertical cutting guides 116, 118facilitate vertical resections, which allow a flat, anterior cut usingthe horizontal cutting guide 114 to be utilized in the surgicaltechnique method. This horizontal and vertical resectioning cuts form atrochlear cavity that allows at least a portion of the trochlear implantto be inlaid. Additionally, the anterior femoral cutting block 100includes the boss 132, which locks the sizing arm 104 to the block 102using BAL SEAL® springs. The anterior femoral cutting block 100 alsoincludes the distal boss 154, which references a previously preparedreference hole defined in the patient's distal femur. Additionally, thebone-confronting side 152 of the cutting block body 102 is contoured tomatch the articulating geometry of the respective trochlear implant.

As discussed above, the sizing arm 104 is coupled to the peg 132extending upwardly from the top side 110 of the cutting block body 102.As shown in FIG. 7, the sizing arm 104 includes an elongated shaft 200,a angled arm 202, and a proximal end shaft 204. The proximal end shaft204 is offset from an axis 206 defined by the elongated shaft 200 viathe angled arm 202. In one embodiment, the proximal end shaft 204 issubstantially parallel to the axis 206, but may be angled with respectthereto in other embodiments. In use, as discussed below, the sizing arm104 is used to reference the anterior cortex of the patient's femur. Theproximal end shaft 204 is angled about three degrees relative to an axis208 defined by the guide pin hole 158 of the distal boss 154 of thecutting block body 102. The bottom side of the proximal end shaft 204 isin alignment with a horizontal cutting plane 210 defined by thehorizontal cutting guide 114. The sizing arm 104 may be used to predictor otherwise identify the orientation and location of the anteriorresection.

As discussed above, the anterior femoral cutting block 100 is used toselect the appropriate size of the trochlear orthopaedic prosthesis 300.In particular, the trochlear prosthesis 300 is selected such that theprosthesis 300 is positionable within the cutting block 100 such thatthe distal end of the prosthesis 300 is received in the contouredbone-confronting surface 152 of the cutting block body 102 and thesuperior end of the prosthesis 300 contacts the sizing arm 104. When sopositioned, the bottom side of the superior end of the prosthesis 300 issubstantially planar with the cutting plane 210 defined between thehorizontal cutting guide 114 and the proximal end shaft 204 of thesizing arm 104.

Referring back to FIG. 1, after the anterior femoral cutting block 100has been sized according to the particular trochlear orthopaedicprosthesis 300 to be implanted and the patient's anatomy, the cuttingblock 100 is positioned on the distal end of the patient's femur. To doso, as illustrated in FIG. 8, a positioning clamp 310 is coupled to thecutting block body 102. The clamp 310 is secured to the body 102 via thebase 138. As discussed above, the apertures 140 and tabs 142 of the base138 provide a structure to which the positioning clamp 310 is coupled.The clamp 310 may be held by the orthopaedic surgeon or other healthcareprovider while positioning the cutting block 100 on the patient's femur.The cutting block 100 is positioned on the distal end of the patient'sfemur such that the sizing arm 104 references the anterior cortex of thepatient's femur and the distal tab 160 references the distal articularcartilage (i.e., the reference point determined in block 12) of thepatient's femur. When so positioned, the bottom side of the distal boss160 is about two to three millimeters from the roof of the intercondylarnotch. Such positioning of the cutting block 100 facilitates the formingof a similarly positioned trochlear cavity and, thereby, positions thetrochlear orthopaedic prosthesis 300 about two to three millimeters fromthe roof of the intercondylar notch.

Referring back to FIG. 1, after the anterior femoral cutting block 100has been properly positioned on the distal end of the patient's femur, apilot or starter hole is drilled into the distal end of the patient'sfemur in step 18. To do so, the orthopaedic surgeon uses the guide pinhole 158 of the block 100 as a drill guide to establish the pilot hole.After the pilot hole has been formed in the patient's distal femur, theanterior femoral cutting block 100 is removed from the patient's femurand a reference hole is formed in the distal end of the patient's femurin block 20. To do so, the orthopaedic surgeon uses a pilot drill bit400, which references the pilot hole formed in step 18. As illustratedin FIG. 9, the drill bit 400 includes a mounting end 402 configured tobe coupled to an orthopaedic drill, a shank 404 extending from themounting end 402, and a drill bit end 406. Illustratively, the mountingend 402 of the orthopaedic pilot drill bit 400 includes a Hudson end tofacilitate quick intraoperative assembly and use with drills equippedwith Hudson-type adaptors. The drill bit end 406 includes a collar 408,drill flutes 410, and a starter bit 412 that extends from the drillflutes 410. Illustratively, the drill flutes 410 have a length 414 ofabout 5.5 millimeters and a diameter 416 of about 10 millimeters. Inuse, the collar 408 operates as a depth stop to limit the depth to whichthe drill bit 400 advances into the distal end of the patient's femur.That is, collar 408 is configured to reference the surrounding cartilageand restrict or limit the advancement of the drill bit 400 further intothe patient's bone.

In use, the orthopaedic surgeon positions the starter bit 412 in thepilot hole established in step 16. The pilot hole guides the drill bit400 as the drill flutes 410 establish a reference hole 450 in the distalend of the patient's femur as illustrated in FIG. 10. The diameter 416of the drill flutes 410 is sized such that the posterior-most point ofthe reference hole 450 defined by the flutes 410 corresponds to thedistal tip 302 of the trochlear orthopaedic prosthesis 300 (see FIG. 7)when the prosthesis 300 is secured to the patient's femur. That is, themost posterior edge of the reference hole 450 formed by the drill flutes410 defines the position of the distal tip 302 of the trochlearorthopaedic implant 300. Additionally, because the collar 408 referencesthe surrounding cartilage, the articulating surface of the distal tip ofthe trochlear orthopaedic implant 300 is substantially parallel or flushwith the surrounding cartilage when the implanted in the bone of thepatient.

Referring back to FIG. 1, after the reference hole 450 has been definedin the distal end of the patient's femur via use of the drill bit 400,the anterior femoral cutting block 100 is coupled to the patient's femurand oriented in step 22. To do so, as shown in FIG. 11, the positioningtool 310 is coupled to the cutting block 100 and used to position thecutting block body 100 on the distal end of the patient's femur. Theanterior femoral cutting block 100 is positioned such that the distalboss 154 of the cutting block body 102 is received in the reference hole450 established in step 20. Once the distal boss 154 is positioned inthe reference hole, the anterior femoral cutting block 100 is aligned.To do so, the anterior femoral cutting block 100 is positioned such thatthe proximal end shaft 204 of the sizing arm 104 is centered on thepatient's femur. Additionally, as discussed above, the Varus/Valgusalignment of the cutting block body 102 can be evaluated by assessingthe quality of fit or conformity of each side of the bone-confrontingside 152 of the block body 102.

The axial alignment of the anterior femoral cutting block 100 is alsoestablished in step 22. To do so, the top surfaces 128, 130 of the sidewalls 120, 122 (see FIG. 3) are aligned with the “sky-line” of theassociated condyles of the patient's femur. That is, the orthopaedicsurgeon may rotate or otherwise move the cutting block body 102 of theblock 100 until each of the top surfaces 128, 130 is aligned with therespective femoral condyle. In addition, the reference line 131 of theupper body 104 may be used to guide the axial positioning of the cuttingblock body 102.

After the anterior femoral cutting block 100 is coupled and aligned tothe patient's femur, the cutting block 100 is secured to the distal endof the patient's femur in step 24. The anterior femoral cutting block100 may be secured via use of a number of bone pins, screws, or similarfasteners. The fasteners may be secured into the femur of the patientthrough the pin guide holes 156, 158. As discussed above, the superiorpin hole 156 is angled to prevent or otherwise limit the anteriorfemoral cutting block 100 from backing off the bone pins during use(e.g., from vibrations generated by a bone saw).

Referring back to FIG. 1, after the anterior femoral cutting block 100has been secured to the patient's femur, the orthopaedic surgeonperforms a number of resectioning cuts using the cutting block 100 insteps 26 and 28. In step 26, the orthopaedic surgeon establishes twovertical bone resectioning cuts using a bone saw 460 equipped with avertical-cutting bone saw blade 462 as shown in FIG. 12. To do so, thevertical cutting guides 116, 118 of the cutting block body 102, are usedas guides for the bone saw blade 462. During use, the orthopaedicsurgeon may position the vertical bone saw blade 462 against the sidewalls 120, 122 that define, in part, the vertical cutting guides 116,118, respectively. As shown in FIG. 13, because the vertical cuttingguide 118 is angled relative to the vertical cutting guide 116, theamount of bone removed and not replaced by a portion of the trochlearprosthesis 300 is reduced. The amount of bone removed and not replace bythe trochlear prosthesis 300 is simulated or otherwise approximated inFIG. 13 via a triangular indicator 470. It should be appreciated thatthe triangle 470 (i.e., the amount of bone removed and not replaced bythe implant 300) would be substantially larger if the vertical cuttingguides 116, 118 were parallel.

After the vertical bone resectioning cuts have been established in step26, the orthopaedic surgeon uses the anterior femoral cutting block 100to perform a horizontal resectioning cut using the horizontal cuttingguide 114. To do so, as shown in FIG. 14, the orthopaedic surgeon maycouple an oscillating saw blade 464 to the bone saw 460 or otheroscillating bone saw and position the blade 464 in the horizontalcutting guide 114. During use, the orthopaedic surgeon may position theblade 464 against the bottom wall of the guide 114. It should beappreciated that the horizontal resectioning cut intercepts thepre-established vertical resection cuts to define a portion of thepatient's femur that is subsequently removed. By removing the femoralportion, a trochlear cavity sized to receive the trochlear prosthesis300 is established in the patient's anterior femur. As such, via use ofthe cutting guides 114, 116, 118, the femur of the patient is preparedfor receiving the trochlear orthopaedic prosthesis 300.

After the orthopaedic surgeon has performed all of the bone cuts usingthe anterior femoral cutting block 100, the cutting block 100 is removedand a finishing burring guide 600 is attached to the patient's femur instep 30. As illustrated in FIGS. 15 and 16, in one embodiment, theburring guide 600 includes a frame 602 defining a superior opening 604and an inferior opening 606. The guide 600 includes a distal boss 608,which is configured to be received in the reference hole 450 defined inthe patient's bone in step 20. Additionally, the guide 600 includes apin guide hole 610 defined through the distal boss 608, which ispositioned to receive the bone pin used to secure the cutting block body102 to the patient's femur via the guide pin hole 158. The guide 600also includes a distal tab 612 that extends downwardly from the frame602. Similar to the tab 160 of the cutting block body 102, the tab 612is configured to reference the surrounding cartilage of the patient'sfemur.

As shown in FIG. 16, the burring guide 600 also includes a base 614coupled to a proximal end of the frame 602. The base 614 is configuredto be received in the proximal portion of the trochlear cavity formed insteps 26, 28 of the method 10. That is, the base 614 includes a bottomsurface 616 configured to abut or confront the resectioned bone of thepatient's femur. The base 614 includes a number of mounting holes 618for further securing the guide 600 to the patient's femur.

As illustrated in FIG. 17, the burring guide 600 is coupled to thedistal end of the patient's femur such that the distal boss 608 isreceived in the reference hole 450. To do so, the guide pin 650 that wasused to secure the cutting block body 102 (via the guide pin hole 158 ofthe distal boss 154) is received in the guide pin hole 610 defined inthe distal boss 608. The burring guide 600 is slid forward along theguide pin 650 and positioned such that the distal boss 608 is receivedin the reference hole 450. Additionally, the base 614 is received in thetrochlear cavity defined in steps 26, 28 and contacts or abuts theresection bone of the patient's femur. The burring guide 600 may befurther secured to the patient's femur via use of a number of Steinmanpins, bone screws, or other fasteners positioned in the mounting holes618. The base 614 of the guide 600 has a thickness 620 (see FIG. 16)that is substantially equal to the thickness of the anterior portion ofthe trochlear orthopaedic prosthesis 300. As such, the upper ledges ofthe base 614 may be used by the surgeon to confirm the anteriorresection depth relative to the surrounding bone.

As shown in FIG. 18, the base 514 has a width 622 that is less than thewidth of the selected trochlear orthopaedic implant 300. The width 622is so sized due to the angled vertical resection that is establishedusing the cutting block 100 in steps 26, 28. That is, because of theangled cut established using the vertical cutting guide 118, theproximal end of the burring guide 600 is narrower to allow the proximalend of the guide 600 to slide within the narrowest width of thetrochlear cavity defined in the patient's femur in steps 26, 28.

Referring back to FIG. 1, after the finishing guide 600 is attached tothe patient's femur as discussed above, the trochlear cavity formed inthe patient's femur is further defined and/or enlarged via a burringprocess in step 32. To do so, the frame 602 of the guide 600 is used asa burring guide for a burring bit. As illustrated in FIG. 19, in oneembodiment, a burring bit 700 that may be used with the finishing guide600 includes an elongated shaft 702, a collar 704, and a burring end706. The burr bit 700 also includes a washer 708 positioned around theshaft 702 between the collar 704 and the burring end 706. The washer 708includes a circular collar 710 and a cylindrical neck 712 extendingdownwardly from the collar 710. As discussed in more detail below, thecollar 710 of the washer 708 is used as a movable guide or rest againstthe burring guide 600. Illustratively, the washer 708 is a PEEK™ washer.

In use, as illustrated in FIG. 20, the burring bit 700 is inserted inone of the openings 604, 606 of the burring guide 600. The collar 704 ofthe burring bit 700 controls the depth to which the burring bit 700advances into the patient's bone. The burring bit 700 may be used toresect additional bone by moving the burring bit 700 along the frame602. When doing so, the washer 708 contacts the frame 602. Theinterfacing of the washer 708 to the frame 602 may reduce heat generatedduring the cutting operation. The washer 708 may or may not rotate withthe elongated shaft 702 of the burring bit 700. The burr bit 700 may bemoved along the frame 602 while keeping the washer 708 in contact withthe frame 602.

Referring back to FIG. 1, after the trochlear cavity is initially burredin step 32 using the burring guide 600 and the burring bit 700, atrochlear trial is positioned in the trochlea cavity and the “fit” ofthe trochlear trial is determined in step 34. In one particularembodiment, the trochlea trial is formed from a substantiallytransparent material, such as a plastic material, to allow theorthopaedic surgeon to visually inspect the “fit” of the trochleartrial. If required, the trochlear cavity may be further detailed usingthe burring bit 700 in step 36 and the trochlear trial may berepositioned in the trochlear cavity. The blocks 34 and 36 may berepeatedly performed to ensure a proper fit of the trochlear trial.

Once satisfied of the trochlear trial fit, peg holes for receiving thepegs of the trochlear orthopaedic prosthesis 300 are formed in thepatient's femur. To do so, in step 38, the orthopaedic surgeon positionsa pegless trochlear prosthetic trial 800 in the trochlear cavity formedin the patient's femur in step 38. As shown in FIG. 21, in oneembodiment, the pegless trochlear prosthetic trial 800 includes a body802 shaped substantially similar to the trochlear prosthesis 300. Thebody 802 includes an outer or top surface 804 and three drill guideholes 806, 808, 810. The drill guide holes 806, 808, 810 are positionedon the body 802 of the trial 800 at locations corresponding to the pegsof the trochlear orthopaedic prosthesis 300. As discussed below, thedrill guide holes 806, 808, 810 provide a guide for establishing pegholes in the patient's femur.

In the illustrative embodiment, the guide holes 806, 808 are locatedsuperiorly relative to the guide hole 810 and are substantially parallelto each other in the medial-lateral direction. Each of the guide holes806, 808 includes an opening 812, 814, respectively, recessed orpartially recessed relative to the outer surface 804 of the trial 800. Arecess flange 813, 815 is defined around or partially around eachopening 812, 814. The trochlear prosthetic trail 800 also includes amounting platform 816 positioned inferiorly relative to the guide holes806, 808. The mounting platform 816 is recessed relative to the uppersurface 804 of the trial 800. The mounting platform 816 is shaped toreceive a base of a trochlear drill guide 900 as discussed in moredetail below.

In the illustrative embodiment of FIG. 21, the mounting platform 816includes a recessed area 820 having a generally wedge or triangularshape. However, the recessed area 820 may have other shapescorresponding to the base of the drill guide 900 in other embodiments.An opening 818 of the guide hole 810 is located in the recessed area 820of the mount platform 816. Additionally, the trochlear prosthetic trail800 includes a mounting aperture 822 defined in the recessed area 820 ofthe mount platform 816. The mounting aperture 822 provides a location towhich the drill guide 900 may be secured to the trial 800 as discussedin more detail below. As such, in some embodiment, the mounting aperture822 may be threaded and configured to receive a bolt or similar fastenerto secure the drill guide 800 to the trochlear prosthetic trial 800. Inthe illustrative embodiment, the mount platform 816 is keyed. That is,the mount platform 816 includes key recess area 824, which is incommunication with the recessed area 820. Illustratively, the key recessarea 824 extends from a side of the recessed area 820, but may bepositioned in other locations in other embodiments. The key recess area824 ensures that the drill guide 900 is secured to the trial 800 in theproper orientation as discussed in more detail below.

After the trochlear prosthetic trial 800 has been positioned in thetrochlear cavity formed in the patient's femur, the trochlear drillguide 900 is attached or secured to the trochlear trial 800 in step 40.As illustrated in FIGS. 22-24, in one embodiment, the trochlear drillguide 900 includes a body 902 and a mount 904 extending from the body902. Illustratively, the body 902 has a substantially oval shape, butmay have other shapes in other embodiments. The illustrative body 902includes substantially planar upper surfaces 906, 908 and a curvedsidewall 910 extending between the upper surfaces 906, 908. Twopassageways 912, 914 are defined through the body 902. Each of thepassageways 912, 914 include an opening 916, 918, respectively, definedin each of the upper surfaces 906, 908.

The illustrative drill guide 900 also includes two drill guide bushings920, 922 positioned in the passageways 912, 914, respectively. However,it should be appreciated that, in other embodiments, the drill guide 900may include a single or multiple bushings positioned in correspondingpassageways. The bushings 920, 922 are separately movable within thepassageways in a direction 924 (see FIG. 23) toward and away from theupper surfaces 906, 08. In the illustrative embodiment, the drill guidebushings 920, 922 are retained in the passageways 912, 914,respectively. That is, the drill guide bushings 920, 922 are movable inthe passageways 912, 914, but cannot be removed therefrom. However, inother embodiments, the drill guide bushings 920, 922 may be removablefrom the passageways 912, 914. Each of the drill guide bushings 920, 922includes a drill guide passageway 924, 926 defined thorough and amounting collar 928, 930 at both ends of the bushing 920, 922. In use,when the drill guide 900 is coupled to the trochlear trial 800, themounting collars 924, 926 independently contact the recessed flanges813, 815 of the trial 800 and the drill guide passageways 924, 926 alignwith the drill guide holes 806, 808 of the trail 800.

As discussed above, the bushings 920, 922 are independently positionablewithin their respective passageway 912, 914. The position of thebushings 920, 922 and the thickness of the recessed flanges 813, 815 ofthe trochlear trial 800 define the depth the peg holes are drilled intothe patient's femur (i.e., the orthopaedic drill stops advancing when itcontacts the bushing 920, 922). As such, the trochlear drill guide 900is usable with trochlear trials of various sizes. That is, because thebushings 920, 922 are independently adjustable, the drill guide 900 maybe used with trials 800 having various dimensions such as thickness andoverall size.

As shown in FIG. 22, the mount 904 includes a mount base 940, 942 oneach upper side 944, 946 of the mount 904. The mount bases 940, 942 areshaped and sized to be received in the recessed mount platform 816 ofthe trial 800. In the illustrative embodiment, each of the mount bases940, 942 are keyed and include a key protrusion 948, which is configuredto be received in the key recess area 824 of the recessed mount platform816 which the drill guide 900 is coupled to the trial 800. The keyprotrusion 948 and the key recess area 824 cooperate to limit theorientation of the trochlear drill guide 900. That is, the trochleardrill guide 900 is configured to couple to a right knee trochlear trialin one configuration and couple to a left knee trochlear trial in asecond configuration. To do so, the surgeon simply flips the drill guide900 over such that the correct mount base 940, 942 is received in therecess mount platform 816. In this way, the drill guide 900 is usablewith trochlear prosthetic trials 800 designed for either right or leftknees (as well as different sizes of right and left knee trials 800 asdiscussed above)

The trochlear drill guide 900 also includes a drill guide passageway 950and a fastener passageway 952 defined through the mount 904. Each of thepassageways 950, 952 include a respective opening 954, 956 defined oneach mount base 940, 942. When the trochlear drill guide 900 is attachedto the trochlear prosthetic trial 800, the drill guide passageway 950aligns with the guide hole 810 of the trial 800 and the fastenerpassageway 952 aligns with the mounting aperture 822 of the trial 800.As shown in FIG. 24, the trochlear drill guide 900 may be secured to thetrochlear prosthetic trial 800 by inserting a lock rod, bolt, or otherfastener 960 through the fastener passageway 952 and threading thefastener 960 into the mounting aperture 822 of the trial 800. When sosecured, the drill guide passageways 924, 926, 950 align with the drillguide holes 806, 808, 810 of the trial 800 as discussed above.

After the trochlear drill guide 900 has been secured to the trochlearprosthetic trial 800, the orthopaedic surgeon may drill the peg holesinto the patient's surgically-prepared femur using the drill guide 900and the trial 800 in step 42. To do so, as illustrated in FIG. 25, abone drill bit is inserted into each of the drill guide passageways 924,926, 950. After a peg hole has been established in the patient's femur,the orthopaedic surgeon may insert a locking or stabilizing rod into therelevant drill guide passageway 924, 926, 950 to keep the guide 900 andtrial 800 aligned with previously drilled peg holes while the remainingpeg holes are established.

After the orthopaedic surgeon has formed the peg holes in the patient'sfemur, the orthopaedic surgeon may subsequently implant the trochlearprosthesis 300 into the patient's surgically-prepared femur. Asdiscussed above, because the anterior femoral cutting block 100 was usedto establish the trochlear cavity, the trochlear prosthesis 300 isinlaid into the patient's femur rather than resting on an outer surfaceof the femur.

While the disclosure has been illustrated and described in detail in thedrawings and foregoing description, such an illustration and descriptionis to be considered as exemplary and not restrictive in character, itbeing understood that only illustrative embodiments have been shown anddescribed and that all changes and modifications that come within thespirit of the disclosure are desired to be protected.

There are a plurality of advantages of the present disclosure arisingfrom the various features of the methods, devices, and assembliesdescribed herein. It will be noted that alternative embodiments of themethods, devices, and assemblies of the present disclosure may notinclude all of the features described yet still benefit from at leastsome of the advantages of such features. Those of ordinary skill in theart may readily devise their own implementations of the methods,devices, and assemblies that incorporate one or more of the features ofthe present invention and fall within the spirit and scope of thepresent disclosure as defined by the appended claims.

The invention claimed is:
 1. A trochlear drill guide comprising: a bodyhaving a first passageway and a second passageway defined therethrough;a first drill guide bushing positioned in the first passageway, thefirst drill guide bushing being movable within the first passageway andincluding a first inner passageway defined therethrough; and a seconddrill guide bushing positioned in the second passageway, the seconddrill guide bushing being movable within the second passageway andincluding a second inner passageway defined therethrough, wherein thefirst and second drill guide bushings are separately movable alonglongitudinal axes defined by the respective first drill guide bushingand second drill guide bushing that extend collinearly with therespective first passageway and second passageway.
 2. The trochleardrill guide of claim 1, wherein: the first drill guide bushing includesa first end, a first collar coupled to the first end, a second endopposite the first end, and a second collar coupled to the second end,the first drill guide bushing being movable within the first passagewaybetween a first position in which the first collar extends out of thefirst passageway and a second position wherein the second collar extendsout of the first passageway, and the second drill guide bushing includesa third end, a third collar coupled to the third end, a fourth endopposite the third end, and a fourth collar coupled to the fourth end,the second drill guide bushing being movable within the secondpassageway between a third position in which the third collar extendsout of the second passageway and a fourth position wherein the fourthcollar extends out of the second passageway.
 3. The trochlear drillguide of claim 1, further comprising a mount coupled to the body andextending therefrom, the mount including a first mounting base locatedat a first end and a second mounting base located at a second endopposite the first end, wherein the mount defines a keyed structure tobe received in a corresponding keyed recess.
 4. The trochlear drillguide of claim 3, wherein the mount includes a first keyed protrusionextending from a first side of the first mounting base and a secondkeyed protrusion extending from a second side of the second mountingbase.
 5. The trochlear drill guide of claim 1, further comprising atrial having a trial body and a first drill guide opening and a seconddrill guide opening extending through the trial body, wherein the firstinner passageway of the first drill guide bushing is collinearly alignedwith the first drill guide opening, and the second inner passageway ofthe second drill guide bushing is collinearly aligned with the seconddrill guide opening when the trial body is coupled to the body.
 6. Thetrochlear drill guide of claim 5, wherein the trial body includes afirst flange extending around the first drill guide opening and a secondflange extending around the second drill guide opening, wherein thefirst flange engages the first drill guide bushing to position the firstdrill guide bushing within the first inner passageway, and the secondflange engages the second drill guide bushing to position the seconddrill guide bushing within the second inner passageway.
 7. A trochleardrill guide system comprising: a guide body having a first passagewayand a second passageway defined therethrough; a first drill guidebushing positioned in the first passageway, the first drill guidebushing being movable within the first passageway and including a firstinner passageway defined therethrough, wherein the first drill guidebushing includes a first end, a first collar coupled to the first end, asecond end opposite the first end, and a second collar coupled to thesecond end; and a second drill guide bushing positioned in the secondpassageway, the second drill guide bushing being movable within thesecond passageway and including a second inner passageway definedtherethrough, wherein the second drill guide bushing includes a thirdend, a third collar coupled to the third end, a fourth end opposite thethird end, and a fourth collar coupled to the fourth end, wherein thefirst and second drill guide bushings are separately movable, whereinthe first and second drill guide bushings are movable along longitudinalaxes defined by the respective first and second passageways, the firstdrill guide bushing being movable within the first passageway between afirst position in which the first collar extends out of the firstpassageway and a second position wherein the second collar extends outof the first passageway, and the second drill guide bushing beingmovable within the second passageway between a third position in whichthe third collar extends out of the second passageway and a fourthposition wherein the fourth collar extends out of the second passageway.8. The trochlear drill guide system of claim 7, further comprising amount coupled to the guide body and extending therefrom, the mountincluding a first mounting base located at a first end and a secondmounting base located at a second end opposite the first end, whereinthe mount defines a keyed structure to be received in a correspondingkeyed recess.
 9. The trochlear drill guide system of claim 8, whereinthe mount includes a first keyed protrusion extending from a first sideof the first mounting base and a second keyed protrusion extending froma second side of the second mounting base.
 10. The trochlear drill guidesystem of claim 7, further comprising: a trial having a trial bodyconfigured to be coupled to the guide body, a first drill guide openingextending through the trial body, and a second drill guide openingextending through the trial body, wherein the first inner passageway ofthe first drill guide bushing is collinearly aligned with the firstdrill guide opening and the second inner passageway of the second drillguide bushing is collinearly aligned with the second drill guide openingwhen the trial is coupled to the guide body.
 11. The trochlear drillguide of claim 10, wherein the trial body includes a first flangeextending around the first drill guide opening and a second flangeextending around the second drill guide opening, wherein the firstflange engages the first drill guide bushing to position the first drillguide bushing within the first inner passageway, and the second flangeengages the second drill guide bushing to position the second drillguide bushing within the second inner passageway.